Assemb. Richard Gottfried, a Manhattan Democrat who chairs the Health Committee in the State Assembly, said that marijuana is widely available on the black market and casual users are unlikely to negotiate the state's highly regulated medical marijuana system, which bars the sale of the drug in smokable form. Approved forms include liquids and oils administered orally or through vapors.

"Someone who wants to get stoned is not going to be doing it with medical marijuana," he said.

Gottfried said common sense would be required and likened the issue of employee medical marijuana use to other restricted drugs.

Bloomfield Industries, one of five companies selected to manufacture and distribute medical marijuana, has proposed to open a dispensary in a Lake Success office building. Columbia Care NY LLC's plan to open a dispensary in Riverhead has encountered opposition.

Panelist Ed Draves, a partner at Albany lobbying firm Bolton-St. Johns LLC, said the New York State law places tight controls on the marijuana, requiring a wireless tracking tag to be attached to each plant and limiting access to dispensaries.

"Only the patient or caregiver can come in," he said.New York is one of more than 20 states to approve medical marijuana.